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lukeoddy_276909's avatar
lukeoddy_276909
Icon for Nimbostratus rankNimbostratus
Feb 08, 2018

LTM Cipher list - NULL

Hi All,

 

Running into a problem with building cipher lists.

 

Trying to build a Cipher list that uses TLS1.2 NULL compression, on LTM 13.0 HF3.

 

Continued in comment below

 

  • [Continued from above, for some reason my post was being flagged as Spam, wouldn't let me post all this as a question]

    Here's the output for all NULL ciphers:

    tmm --clientciphers 'NULL'
           ID  SUITE                            BITS PROT    METHOD  CIPHER    MAC     KEYX
     0:     2  NULL-SHA                           0  SSL3    Native  NULL      SHA     RSA
     1:     2  NULL-SHA                           0  TLS1    Native  NULL      SHA     RSA
     2:     2  NULL-SHA                           0  TLS1.1  Native  NULL      SHA     RSA
     3:     2  NULL-SHA                           0  TLS1.2  Native  NULL      SHA     RSA
     4:     1  NULL-MD5                           0  SSL3    Native  NULL      MD5     RSA
     5:     1  NULL-MD5                           0  TLS1    Native  NULL      MD5     RSA
     6:     1  NULL-MD5                           0  TLS1.1  Native  NULL      MD5     RSA
     7:     1  NULL-MD5                           0  TLS1.2  Native  NULL      MD5     RSA
    

    Here is my attempt at excluding all the non-TLSv1.2 ciphers, which doesn't work as expected:

    tmm --clientciphers 'NULL:!SSLv3:!TLSv1:!TLSv1_1'
           ID  SUITE                            BITS PROT    METHOD  CIPHER    MAC     KEYX
     0:     2  NULL-SHA                           0  SSL3    Native  NULL      SHA     RSA
     1:     2  NULL-SHA                           0  TLS1    Native  NULL      SHA     RSA
     2:     2  NULL-SHA                           0  TLS1.1  Native  NULL      SHA     RSA
     3:     2  NULL-SHA                           0  TLS1.2  Native  NULL      SHA     RSA
     4:     1  NULL-MD5                           0  SSL3    Native  NULL      MD5     RSA
     5:     1  NULL-MD5                           0  TLS1    Native  NULL      MD5     RSA
     6:     1  NULL-MD5                           0  TLS1.1  Native  NULL      MD5     RSA
     7:     1  NULL-MD5                           0  TLS1.2  Native  NULL      MD5     RSA
    

    The syntax "!SSLv3:!TLSv1:!TLSv1_1" seems to work just fine with other cipher lists. For instance, "DEFAULT:!SSLv3:!TLSv1:!TLSv1_1" works as expected, only TLS1.2 and DTLS1 ciphers appear in that list.

    So why is NULL a special case here?

  • JG's avatar
    JG
    Icon for Cumulonimbus rankCumulonimbus

    Not sure why the negation does not work, but there is a better way of achieving the same outcome, i.e. by disabling the insecure protocols via the "Options List" in your SSL profile.